Pianoforte and like mechanically operated string instrument



22, 1935. I w, EVANS 2,017,959

PIANOFORTE AND LIKE MEGHANICALLY OPERATED STRING INSTRUMENT Filed May 18, 1934 2 Sheets-Sheet l @@&a 22, 1935. v w E N 2,017,959

PIANOFORTE AND LIKE MECHANICALLY OPERATED STRING INSTRUMENT Filed May 18, 1934 2 Sheets-Sheet '2 Patented Oct. 22, 1935 UNITED STATES PATENT OFFICE Willie Evans, London, England Application May 18, 1934, Serial No. 726,323 In Great Britain June 30, 1933 16 Claims.

This invention is for improvements in or relating to pianofortes and the like, such as mechanically operated pianos and particularly to what are known as baby-grand pianos.

In the early design of pianos, the strings were arranged to extend side by side in a somewhat similar manner to that of a harp. The bass strings require tobe of a considerable length in order that good tonal qualities can be obtained and thus, in the case of a grand piano where the strings extend away from and in a plane parallel to that containing the keyboard, an instrument of great length from back to front resulted. In a later stage of development, in order to reduce this overall length, cross stringing was adopted. in which the bass strings were arranged to overlap the tenor portion of the remaining groups of strings. An object of the present invention is to provide a piano of small dimensions with good tonal qualities.

According to this invention, a pianoforte or the like is provided with a number of overlapping groups of strings connected at their ends to a framework and spaced away from the soundboard 5 by a number of bridge pieces separate from one another and from said framework, at least two of which bridge pieces are so disposed in relation to one another that strings supported by and extending from one bridge piece, pass clear over the other and at least one pair of which bridge pieces (e. g. the bridge piece furthest from the centre of the soundboard) is supported clear of the soundboard by one or more lever arms, at least one of which lever arms is disposed above and fixed to the upper surface of the soundboard in the locality of the other bridge piece. Preferably, the lever arm carrying one of the pair of bridge pieces is secured to the soundboard beneath the other bridge piece.

It will be appreciated with this arrangement that the two bridge pieces are connected to one another and the double bridge piece thus formed has a single anchorage to the soundboard.

A feature of the invention consists in that cantilevers are employed which are anchored nearer the centre of the soundboard than is the location of the bridge piece carried by them.

A further feature of the invention consists in that lever arms are provided both above and below said soundboard which lever arms are joined together by a member, or members, which extend freely through a hole, or holes, in the soundboard.

A further feature of the invention consists in that the lever arm which is disposed above the 56 soundboard is attached to the upper side of the soundboard at two or more locations spaced apart in the direction of the length of the strings.

In an arrangement in which two bridge pieces support separate groups of strings and are spaced apart in a direction along the length of the strings, 5 a feature of the invention consists in that one of said bridge pieces is carried by the aforementioned arm which is attached at one end to the other bridge piece and to the soundboard.

A further feature of the invention consists in 10 that said arm is attached at one or more locations to the soundboard under that bridge piece which is supported clear of the soundboard. Alternatively, the arm may be attached to the soundboard between the two bridge pieces. 15

Preferably, a single arm is provided for supporting a bridge piece in which case the width of said arm from side to side is approximately the same as the length of the bridge piece and said arm is attached only partly across its width to 20 said soundboard.

The invention is particularly applicable to a piano having three overlapping groups of strings supported by three separate bridge-pieces in such an arrangement, the bridge piece for the mid-tone 25 group of strings is so disposed that the strings of the high tone group pass over it and the bridge for the mid-tone group is supported clear of the soundboard by one or more lever arms which extend towards the high tone bridge piece. 30

Other features of the invention are hereinafter described and claimed.

The following is a description of a number of embodiments of the invention as applied to a baby-grand piano, reference being made to the 5 accompanying drawings, in which- 7 Figure l is a plan view of the instrument with the lid removed;

Figure 2 is an enlarged plan view of the arrangement of the bridge pieces; 40

Figure 3 is a section on the line 3-3 of Figure 2;

Figure 4 is an elevation of the parts shown in Figure 2 looking in the direction of the arrow 4;

Figure 5 is a similar view to that of Figure 3 45 but in which the lower cantilever arms are arranged to extend beyond that bridge piece nearer the centre of the soundboard.

Figure 6 is a plan view of part of a grand piano, showing a short bridge piece supported by a lever 50 arm attached to the soundboard and to another longer bridge piece;

Figure 7 is a section along the line 'l--'| 01' Figure 6;

Figures 8 to 11 are diagrammatic views similar to Figure 6 and showing alternative methods of mounting the short bridge piece.

It will be seen from Figure 1 that the strings are divided into three groups ||l, II and l2. Group ID includes seventeen bass notes extending from low A to C sharp; group H includes fourteen mid-tone notes extending from D to D sharp; while group I2 includes fifty-four notes extending from E to high A. The strings in group In, which are the longest strings, are inclined at an angle of about 60 to a line side to side of the piano, while the strings of group H, which are arranged immediately beneath group I0, cross the strings of group H1 at an angle of about 40. The remaining group I2 containing the treble and tenor strings is arranged in a fan-shaped manner so that the longest tenor string is arranged at an angle of about 60 to a line extending from side to side of the piano and extends across beneath the strings of the other two groups. As is usual, the ends of the strings are connected to a metal frame |3 having cross brace members M. The groups of strings IO, N, |2 are supported near the ends remote from the keyboard by separate wooden bridge pieces I5, I 6 and IT respectively. The bridge piece bears directly on the soundboard l8, but the bridge piece I6 is secured in a manner now to be described with reference to Figures 2 and 3.

It will be noted from Figure 3 that the bridge piece I6 is spaced away from and above the soundboard l8 and is carried by cantilever arms I9, 2|! and 2|. The cantilever arm H], which is arranged above the soundboard is formed from a strip of beechwood about r"; of an inch in thickness for the greater part of its length but is thickened at 9 to about inch where it is secured beneath the bridge piece I1. With this arrangement it is spaced away from the soundboard for the greater part of its length by of an inch. The bridge piece I6 is secured to the free end of the lever arm I!) by glueing or by wood screws or by both, while the other end of the lever arm is secured within a cut away portion on the bridge piece IT as seen in Figure 4. A tongue and slot joint 28 is provided on one side of the lever arm.

The two cantilever arms 20, 2| which are arranged beneath the soundboard are also formed from beechwood and are about 1% inches wide and 2 inches in overall depth. However, they are cut away between their ends to a depth of about 1 inch in order to clear the strengthening bars 21 on the underside of the soundboard. Each of them is secured at one end to the soundboard I8 by two wood screws 22 which extend up through the foot 23 formed by the cut away portion and into the bridge piece IT. The free ends of the cantilever arms extend beneath the bridge piece I6 and are so dimensioned as to be spaced beneath the soundboard by a distance of about V inch. Each free end carries a pillar 24 which extends up through a hole 25 in the soundboard and abuts against the underside of the lever arm IS. The pillars, which are formed from hard wood such as beech, are about inch in diameter and are retained in position by screws 29 which extend through them and the lever arms.

In the construction shown in Figure 5, the two cantiliver arms 20 and 2| are longer than the cantilever arm l9 and are secured to the soundboard at locations disposed on the opposite side of the fixed bridge piece IT to that side where the bridge piece l6, which they carry, is located. The said lever arms may extend to a distance of about four inches beyond the fixed bridge piece and are secured to the soundboard by wood screws 30.

The bridge piece l5, shown in Figure 1, is carried by a single cantilever arm 8 which is secured at one end to the top face of the soundboard. It will be appreciated that the bridge piece If: is the highest so as to permit the strings supported thereby to pass over the other groups of strings and over the bridge piece ll, while the bridge piece I5 is of such a height as to permit the group of strings H to pass over the bridge piece I! and between the groups of strings I0 and |2.

It will be appreciated that many modifications may be made to the details of the above construction without departing from the scope of this invention. For example, fulcrums 26, as shown dotted in Figure 3, might be arranged between the soundboard l8 and the lever arm l9, also between the soundboard and the lever arms 20 and 2| at a location intermediate of the free end and the fixed end of the arm. In the construction shown in Figure 5, the iulcrums above and below the soundboard may be disposed at a distance apart; furthermore, the pillar 24 between the lever arm H) and the lever arms 20 and 2| might be disposed nearer the bridge piece I! or a number of pillars might be arranged to extend between each of the lever arms 20 and 2| and the lever arm it, appropriate holes being made in the soundboard.

Referring to Figures 6 and 7, the short bridge piece H0 is carried by a lever arm III which is fixed at one end to the soundboard ||2 through the intermediary of a spacing member l3; the spacing member is glued to both the lever arm and the soundboard. The longer bridge piece I I4 is fixed by glue and screws overthe end of the lever arm. It will be noted from Figure 6 that the area of contact between the spacing member H3 and the soundboard is greater than the area of contact between the lever arm and the bridge piece H4. The lever arm is also fixed to the soundboard by two additional spacing members H5, H6 which are located between the two bridge pieces I I0 and I H at locations nearer the bridge piece NJ. The spacing members are glued and screwed both to the lever arm and to the soundboard.

In the construction shown in Figure 8, instead of the lever arm I being attached to the soundboard between the two bridge pieces, it is attached to the soundboard beneath the bridge piece ||fl by two spacing members H1, H8 disposed apart.

In the arrangement shown in Figure 9, a single spacing member H9 secures the lever arm to the soundboard beneath the bridge piece H).

The construction shown in Figure 10 is similar to that of Figure 6 with the exception that the distance piece i8 is omitted.

In the construction shown in Figure 11, a single distance piece I2!) is arranged to connect the lever arm to the soundboard between the two bridge pieces.

The constructions described above are particularly suitable for pianos having separate groups of overlapping strings, since it enables the vibrations from the bridge pieces to be transmitted to those parts of the soundboard which provide the best tonal properties and it enables the dimensions of the piano to be reduced very considerably without detriment to tone.

In applying the invention to a piano having three overlapping groups of strings in which the bass register is divided into two parts, the bridge piece I H], such as is shown in the figures above referred to, is arranged to support the higher of the two bass sets of strings, which bridge piece is connected to the bridge piece H4 which supports the treble strings.

I claim:-

1. A pianoforte comprising a soundboard, a framework, three overlapping groups of strings secured-at their ends to said framework, three bridge pieces separate from one another and each arranged to support a group of strings on said soundboard, which bridge pieces are so disposed that the mid tone group of strings passes over the bridge piece which supports the high tone group, a lever arm extending between and attached to both the high-tone and mid-tone bridge pieces and means for attaching said lever arm to the upper face of the soundboard beneath the high-tone bridge piece.

2. A. pianoforte comprising a soundboard, a framework, three overlapping groups of strings secured at their ends to said framework, three bridge pieces separate from one another and each arranged to support a group of strings on said soundboard, which bridge pieces are so disposed that the mid tone group of strings passes over the bridge piece which supports the high tone group, a lever arm, the width of which is approximately the same as the length of the high-tone bridge piece, which lever arm extends between and is attached to both the mid-tone and high-tone bridge pieces and is also attached to the upper face of the soundboard at a plurality of locations spaced in the direction of the length of the strings at least one of which locations is beneath said high tone bridge piece.

3. A pianoforte comprising a soundboard, a framework, three overlapping groups of strings secured at their ends to said framework, three bridge pieces separate from one another and each arranged to support a group of strings on said soundboard, which bridge pieces are so disposed that the mid tone group of strings passes over the bridge piece which supports the high tone group, a lever arm, the width of which is approximately the same as the length of the high-tone bridge piece, extending between and attached to both the mid-tone and high-tone bridge pieces, which lever arm is attached only partly across its width to the upper face of the soundboard at a plurality of locations spaced apart in the direction of the length of the strings.

l. A pianoforte comprising a soundboard, a framework, three overlapping groups of strings secured at their ends to said framework, three bridge pieces separate from one another and each arranged to support a group of strings on said soundboard, which bridge pieces are so disposed that the mid tone group of strings passes over the bridge piece which supports the high tone group, a lever arm, the width of which is approximately the as the length of the high-tone bridge piece, extending between and attached to both the midtone and high-tone bridge pieces, which lever arm is attached at one end across the whole of its width to the soundboard beneath the high-tone bridge piece and is also attached between the midtone and high-tone bridge pieces to the soundboard at two separate locations one near each side of the arm.

5. A pianaforte comprising a soundboard, a framework, three overlapping groups of strings secured at their ends to said framework, three bridge pieces separate from one another and each arranged to support a group of strings on said soundboard, which bridge pieces are so disposed that the mid tone group of strings passes over the bridge piece which supports the high tone group, a lever arm, the width of which is approximately the same as the length of the high-tone bridge piece, extending between and attached to both the mid-tone and high-tone bridge pieces, which lever arm is attached to the upper face of the soundboard so that the area of contact between the lever arm and the soundboard is greater than that between the lever arm and the high-tone bridge piece which arm is also attached to the soundboard at least at one locality between the midtone and high-tone bridge piece.s.-

6. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm at least at one point to the upper face of the soundboard.

'7. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm at least at one point to the upper face of the soundboard beneath one of said bridge pieces.

8. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm at least at one point to the upper face of the soundboard beneath the bridge piece nearer the center of the soundboard.

9. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings a plurality of lever arms, certain of which are disposed above the soundboard and extend between and are attached to both said bridge pieces and are also attached at least at one point to the upper face of the soundboard, and certain of which are disposed below the soundboard and attached to the lower face thereof, and a pillar member arranged to extend through an aperture in the soundboard which pillar member is adapted to join together an upper and a lower lever arm.

10. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings a plurality of cantilevers, certain of which are disposed above the soundboard and extend between and are attached to both said bridge pieces, and are also attached at least at one point to the upper face of the soundboard, and certain of which are disposed below the soundboard and attached to the lower face thereof, and a pillar member arranged to extend through an aperture in the soundboard which pillar member is adapted to join together an upper and a lower cantilever.

11. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm at least at one point to the upper face of the soundboard and a fulcrum disposed between said soundboard and lever arm at a locality spaced away from the point of attachment of the lever arm to the soundboard.

12. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm at least at two points to the upper face of the soundboard.

13. A soundboard and bridge piece assemblage for a pianoiorte comprising a pair of bridge pieces supporting overlapping groups of strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm to the upper face of the soundboard at a plurality of locations spaced apart in a direction along the length of the strings.

14. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups and strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm to the upper face of the soundboard at a plurality of locations spaced apart in a direction along the length of the strings at least one of which locations is beneath one of said bridge pieces.

15. A soundboard and bridge piece assemblage for a pianoforte comprising a pair of bridge pieces supporting overlapping groups and strings and spaced apart along the length of the strings, a lever arm extending between and attached to both said bridge pieces and means for attaching said lever arm to the upper face of the soundboard at a plurality of locations disposed between said bridge pieces and spaced apart in a direction along the length of the strings.

16. A pianoforte comprising a soundboard, a framework, three overlapping groups of strings secured at their ends to said framework, three bridge pieces separate from one another and each arranged to support groups of strings on said soundboard, which bridge pieces are so arranged that the mid-tone group of strings passes over the bridge piece which supports the high-tone group of strings, a plurality of lever arms, certain of which are disposed above the soundboard and extend between and are attached to both the mid-tone and high-tone bridge pieces and which are also attached to the upper face of the soundboard beneath said high-tone bridge piece, and certain of which are disposed below the soundboard and attached to the lower face thereof, and a pillar member arranged to extend through an aperture in the soundboard which pillar member is adapted to join together an upper and a lower lever arm.

WILLIE EVANS. 

